Timepiece brake wheel assembly

Abstract

Timepiece brake wheel assembly, including an arbor comprising a first surface cooperating, to guide pivoting, with a second surface of a wheel pivotally mounted on the arbor around a pivot axis, this second surface including one braking surface comprised in a brake shoe subjected to the action of a first spring, in one-piece with the wheel, and arranged to exert a radial force with respect to the pivot axis on the first surface, this assembly including notches forming a comb or a toothing, arranged to retain a finger-piece for discrete value adjustment of the friction exerted by the braking surface on the first surface, this assembly being arranged to be included in a timepiece mechanism or in a timepiece.

What is claimed is: 
     
       1. A timepiece brake wheel assembly, comprising:
 an arbor comprising a first surface cooperating, to guide pivoting, with a second surface of a wheel pivotally mounted on said arbor around a pivot axis, 
 wherein said first surface or respectively said second surface includes at least one braking surface carried by at least a first braking arm subjected to the action of at least a first elastic return means, in one-piece with said arbor or respectively said wheel, and arranged to exert a radial force with respect to said pivot axis on said second surface or respectively said first surface, 
 wherein said brake wheel assembly includes built-in adjustment means for discrete value adjustment of friction exerted by said braking surface on said second surface or respectively said first surface, 
 wherein said built-in adjustment means include a bearing surface arranged to cooperate in abutment and by thrust force with a complementary bearing surface comprised in a brake shoe on a side opposite said braking surface, and 
 wherein said built-in adjustment means include at least a second flexible arm carrying said bearing surface, said second arm being, either radially limited on a first side with respect to said pivot axis and, on a second side opposite to said first side, in abutment on an adjustment device arranged to occupy one of a plurality of discrete positions with respect to said arbor or respectively said wheel, or returned towards said complementary bearing surface of said brake shoe by a second elastic return means. 
 
     
     
       2. The timepiece brake wheel assembly according to  claim 1 , wherein said first surface or respectively said second surface includes, distinct from each other, at least one guide surface having predetermined play, about a pivot axis of said second surface or respectively said first surface, and at least one said braking surface. 
     
     
       3. The brake wheel assembly according to  claim 1 , wherein said second arm is returned towards said complementary bearing surface of said brake shoe by said second elastic return means, and includes at least one finger-piece, or respectively one notch, subjected to the return action of said second elastic return means and arranged to cooperate with only one notch at a time of a plurality of notches comprised in said arbor or respectively said wheel, each notch of said plurality of notches corresponding to a different friction adjustment value. 
     
     
       4. The brake wheel assembly according to  claim 3 , wherein said brake shoe is subjected both to the action of at least a first elastic return means and to the action of said second elastic return means. 
     
     
       5. The brake wheel assembly according to  claim 1 , wherein said second elastic return means is in one-piece with said arbor or respectively said wheel. 
     
     
       6. The brake wheel assembly according to  claim 1 , wherein torque exerted on said brake shoe by said first elastic return means is greater than torque exerted by said second elastic return means. 
     
     
       7. The brake wheel assembly according to  claim 1 , wherein said second arm is radially limited with respect to said pivot axis opposite thereto in abutment on said adjustment device which includes an eccentric adjustment in discrete positions. 
     
     
       8. The brake wheel assembly according to  claim 1 , wherein said wheel is made of single crystal or polycrystalline silicon. 
     
     
       9. The brake wheel assembly according to  claim 1 , wherein said arbor is made of ruby. 
     
     
       10. The brake wheel assembly according to  claim 1 , wherein the assembly comprises only two components which are said arbor and said wheel. 
     
     
       11. The brake wheel assembly according to  claim 1 , wherein said arbor is fixedly mounted on a main plate or a bridge comprised in a timepiece mechanism or movement in which said brake wheel assembly is integrated. 
     
     
       12. A timepiece mechanism comprising:
 at least one brake wheel assembly according to  claim 1 . 
 
     
     
       13. A timepiece comprising:
 at least one brake wheel assembly according to  claim 1 . 
 
     
     
       14. A timepiece brake wheel assembly, comprising:
 an arbor comprising a first surface cooperating, to guide pivoting, with a second surface of a wheel pivotally mounted on said arbor around a pivot axis, 
 wherein said first surface or respectively said second surface includes at least one braking surface carried by at least a first braking arm subjected to the action of at least a first elastic return, in one-piece with said arbor or respectively said wheel, and arranged to exert a radial force with respect to said pivot axis on said second surface or respectively said first surface, 
 wherein said brake wheel assembly includes a bearing surface arranged to cooperate in abutment and by thrust force with a complementary bearing surface comprised in a brake shoe on a side opposite said braking surface to adjust, by a discrete value, friction exerted by said braking surface on said second surface or respectively said first surface, and 
 wherein said assembly includes a second flexible arm carrying said bearing surface, said second arm being either radially limited on a first side with respect to said pivot axis and, on a second side opposite to said first side, in abutment on an adjustment device arranged to occupy one of a plurality of discrete positions with respect to said arbor or respectively said wheel, or returned towards said complementary bearing surface of said brake shoe by a second elastic return.